ECMAScript Built-ins

SSJS runs on the JINT engine with ES3/ES5 compatibility. Most native ECMAScript built-ins work as expected, but some methods are missing or behave incorrectly. This section documents what is safe to use.

For missing methods, see Polyfills and Missing Methods.

Quick Reference

Array Methods

Method	Status	Notes
`arr.push(item)`	✅ Works
`arr.pop()`	✅ Works
`arr.shift()`	✅ Works
`arr.unshift(item)`	✅ Works
`arr.splice(start, count)`	✅ Works
`arr.slice(start, end)`	✅ Works
`arr.join(sep)`	✅ Works
`arr.reverse()`	✅ Works
`arr.sort(fn)`	✅ Works
`arr.indexOf(item)`	⚠️ Use polyfill	May not work
`arr.forEach(fn)`	❌ Missing	Use `for` loop
`arr.map(fn)`	❌ Missing	Use `for` loop
`arr.filter(fn)`	❌ Missing	Use `for` loop
`arr.reduce(fn)`	❌ Missing	Use `for` loop
`arr.some(fn)`	❌ Missing	Use `for` loop
`arr.every(fn)`	❌ Missing	Use `for` loop
`arr.find(fn)`	❌ Missing	ES6, unsupported
`Array.isArray(val)`	❌ Missing	Use `typeof val === "object" && val.length !== undefined`

String Methods

Method	Status	Notes
`str.length`	✅ Works
`str.charAt(i)`	✅ Works
`str.charCodeAt(i)`	✅ Works
`str.indexOf(sub)`	✅ Works
`str.lastIndexOf(sub)`	✅ Works
`str.slice(start, end)`	✅ Works
`str.substring(start, end)`	✅ Works
`str.toUpperCase()`	✅ Works
`str.toLowerCase()`	✅ Works
`str.split(sep)`	✅ Works
`str.replace(search, rep)`	✅ Works	Regex supported
`str.match(regex)`	✅ Works
`str.search(regex)`	✅ Works
`str.trim()`	⚠️ Use polyfill	May be missing
`str.startsWith(sub)`	❌ Missing	ES6, use `indexOf`
`str.endsWith(sub)`	❌ Missing	ES6, use `lastIndexOf`
`str.includes(sub)`	❌ Missing	ES6, use `indexOf !== -1`
`str.repeat(n)`	❌ Missing	ES6, loop instead
`str.padStart(len, ch)`	❌ Missing	ES6, implement manually

Math Object

Method	Status
`Math.abs(x)`	✅ Works
`Math.ceil(x)`	✅ Works
`Math.floor(x)`	✅ Works
`Math.round(x)`	✅ Works
`Math.max(a, b, ...)`	✅ Works
`Math.min(a, b, ...)`	✅ Works
`Math.pow(base, exp)`	✅ Works
`Math.sqrt(x)`	✅ Works
`Math.random()`	✅ Works
`Math.PI`	✅ Works

In This Section

Page	Description
Array Methods	Safe and polyfillable array methods
String Methods	Safe and polyfillable string methods
Math	Math object reference